Method and apparatus for use in ascertaining web strain in a wound roll



Dec. 15, 1964 PUNDYK 161,043

J. 3 METHOD AND APPARATUS FOR USE IN ASCERTAINING WEB STRAIN IN A WOUND ROLL Filed Dec. 21. 1961 I NVEN TOR: JOSEPH H/NDYK ATTORNEY United States Patent l York Filed Dec. 21, 1961, Ser. No. 161,058 4 Claims. (Cl. 738) This invention relates to an improved method of ascertaining the strain existing in the web in a wound roll of web material and to apparatus useful in practicing said method. Such ascertainment is useful as a check upon the tightness of the wind of material in the roll.

An important object of the invention is the provision of such a method which is simple and easily practiced.

Another important object is the provision of simple apparatus which may optionally be employed in practicing the mentioned method.

The strain to be ascertained arises from the fact that, during winding of the web making up the roll, the web has necessarily been under some lengthwise tension so that it could be kept under control to prevent wrinkling or tearing in passing from a supply source, such as a mill roll, to the roll being formed as the wound roll. The web ordinarily undergoes some processing such as printing or slitting in passing from the mill roll to the wound roll. The web in either the mill roll or a later formed wound roll is, of course, under some lengthwise strain or tension and this invention is applicable to the ascertainment of such tension or strain existing in any wound roll of web material.

The principle employed in this method stems from the fact that the difference between the length of a strip of material in its non-tensioned or non-strained condition and the length of the same strip when under tension or strain is directly proportional to the imposed tension or strain.

In the accompanying drawing:

FIGURE 1 is a perspectiveview of a wound web roll including a device which, although not essential, is, nevertheless, useful in ascertaining the strain of the web in the roll in one way of practicing the present method.

FIG. 2 is an enlarged, fragmentary, end elevational view of the upper portion of said roll at a stage of this method at which comparisons of certain measurements will be indicative of the strain in the wound web in the roll.

In practicing this invention, the roll 1, ofwhich the strain of web is to be ascertained, is placed upon a supporting surface such as floor surface 3, and stripped of one or several outer turns of web material which may have become loosened by handling. The remaining outermost turn of web, then, is as taut as originally wound and held thus taut by the weight of the roll resting thereon with the end 5 of the web protruding freely at one side of the bottom of the roll.

In the simplest manner of ascertaining the web strain according to this invention a cut 7 extending axially of the roll and transversely of the web is made at or toward the top of the roll and completely through the outermost turn of the web; the web material at both sides of the turn to remain in intimate association with the roll. This holding of said outer turn may be done manually by one or more attendants or by some suitable holding device as hereinafter described.

In some wound rolls, if it is attempted to cut completely through the outermost turn of web, the sheet may tear before the out can be completed, giving ragged edges which will 'reduce the accuracy of the measurements to be made. In such situations the invention may be practiced by cut, meanwhile, being suitably held to constrain said outer 3,l6l,@i3 Patented Dec. 15,1964

scoring or otherwise weakening the web as a first and greater part of a cut thereacross, and then cutting deeper or completely through the web for the remainder of the latters width. In this way, the out turn of the web pops open, separating cleanly at the. cut so that accurate measurements can be made all along the cut.

Upon being thus cut and while held against fallin away from the roll, said outermost turn becomes freed of its strain or tension and its opposed ends a and .b separate and define between them a space 9 the width of which, in comparison with the circumference of the wound roll, may be taken as an accurate indication of the tension of the web remainingin the roll.

To utilize the stated method with respect to any wound roll, it may be seen that the following formula is applicable:

strain of web in roll change in length under tension non-tensioned length Width of space 9 circumference of roll-width of space 9 In the above formula, the width of space 9 may be omitted from the denominator with negligible error; the formula, thus simplified, being:

It may be found to be more convenient to hold the outer turn of web by a suitable holding device during the mentioned cutting of said outer turn and until the measurement of space 9 has been taken. This invention comprehen-ds the optional use of a holding frame 11 consisting of two U-shaped holding members 13 rigidly interconnected by connecting bars 15 and 16, said frame preferably being of rigid metal rod material. Prior to making the cut '7, the holding frame is positioned and manually held firmly in its position as illustrated in FIG. 1 with the extremities 17 of the holding members pressed against the roll with little more than sutficient pressure than necessary to prevent the outer turn from separating from the roll upon being cut.

Another way of practicing this invention which avoids the necessity of holding the outer turn of the web to prevent it from falling away from the roll is to make the mentioned cut 7 through the two outermost turns or thicknesses of the web material rather than through only a single turn or thickness. In this way, a single sheet of the web material will fall away and become separable Percent strain of web X 108 from the roll and be in strain-released condition. Then,

the strain factor of web remaining to the formula:

length of separated sheet in the roll will accord or, in terms of percent:

percent strain of web in roll: circumference of roll-length of separated sheet length of separated sheet X As this invention or some features thereof may be practiced somewhat differently than herein described, it should claims.

, 3 I claim: 1. The method of ascertaining the strain in web material in a wound roll, comprising cutting the outermost .non-loosened turn ofthe web material completely thereacross to relieve the strain in said turnand therebyperrnit said turn to assume a reduced length as in non-strained condition, and comparing said reduced length to the circumference of the wound roll.

2. The method according to claim 1, wherein said turn 1 is so held against the roll at opposite sides of the cut of said turn that the latter may slip relatively to the next underlying turn of the Web material to form a space between opposed ends of the web material at said cut but may not separate from the roll, and comparing the width of said space to the circumference of the wound roll.

3. The method according to claim 1, wherein said cutting is efiected through the two outermost layers of the web material on the roll to provide a full turn single length of the web material in strain-relieved condition, and comparing the length of said strain-relieved length of material to the circumference of the wound roll.

4. Apparatus for use in ascertaining web strain in a wound roll of web material, comprising a relatively rigid web-holding frame including plural, integral, web-holding members, and spaced parallel connecting bars rigidly interconnecting said members, at corresponding sides thereof, in spaced relationship along a first projected line; said web-holding members each having a pair of webengaging fingers with extremities thereof spaced from each other along a second projected line extending transversely of said first line; and said frame being adapted to be manually held against the surface of an outer turn of web of said roll with said extremities in engagement with said surface at opposite sides of a line at which a cut is to be made, to hold the web of said outer turn against separation from the remainder of the roll.

References Cited by the Examiner UNITED STATES PATENTS 2,187,914 1/40 Reitan 73-95 3,073,156 1/63 Rowe 73l43 RICHARD C. QUEISSER, Primary Examiner.

DAVID SCHONBERG, Examiner. 

1. THE METHOD OF ASCERTAINING THE STRAIN IN WEB MATERIAL IN A WOUND ROLL, COMPRISING CUTTING THE OUTERMOST NON-LOOSENED TURN OF THE WEB MATERIAL COMPLETELY THEREACROSS TO RELIEVE THE STRAIN IN SAID TURN AND THEREBY PERMIT SAID TURN TO ASSUME A REDUCED LENGTH AS IN NON-STRAINED CONDITION, AND COMPARING SAID REDUCED LENGTH TO THE CIRCUMFERENCE OF THE WOUND ROLL. 